refactor(metrics): replace hardcoded time with contants, merge three tickers into one

internal/metrics/period/period.go

@@ -18,16 +18,22 @@ const (
 	MetricsPeriod1h  Filter = "1h"  // @name MetricsPeriod1h
 	MetricsPeriod1d  Filter = "1d"  // @name MetricsPeriod1d
 	MetricsPeriod1mo Filter = "1mo" // @name MetricsPeriod1mo
+
+	Duration5m  = 5 * time.Minute
+	Duration15m = 15 * time.Minute
+	Duration1h  = 1 * time.Hour
+	Duration1d  = 24 * time.Hour
+	Duration30d = 30 * 24 * time.Hour
 )
 
 func NewPeriod[T any]() *Period[T] {
 	return &Period[T]{
 		Entries: map[Filter]*Entries[T]{
-			MetricsPeriod5m:  newEntries[T](5 * time.Minute),
-			MetricsPeriod15m: newEntries[T](15 * time.Minute),
-			MetricsPeriod1h:  newEntries[T](1 * time.Hour),
-			MetricsPeriod1d:  newEntries[T](24 * time.Hour),
-			MetricsPeriod1mo: newEntries[T](30 * 24 * time.Hour),
+			MetricsPeriod5m:  newEntries[T](Duration5m),
+			MetricsPeriod15m: newEntries[T](Duration15m),
+			MetricsPeriod1h:  newEntries[T](Duration1h),
+			MetricsPeriod1d:  newEntries[T](Duration1d),
+			MetricsPeriod1mo: newEntries[T](Duration30d),
 		},
 	}
 }
@@ -68,11 +74,11 @@ func (p *Period[T]) ValidateAndFixIntervals() {
 	defer p.mu.Unlock()
 
 	durations := map[Filter]time.Duration{
-		MetricsPeriod5m:  5 * time.Minute,
-		MetricsPeriod15m: 15 * time.Minute,
-		MetricsPeriod1h:  1 * time.Hour,
-		MetricsPeriod1d:  24 * time.Hour,
-		MetricsPeriod1mo: 30 * 24 * time.Hour,
+		MetricsPeriod5m:  Duration5m,
+		MetricsPeriod15m: Duration15m,
+		MetricsPeriod1h:  Duration1h,
+		MetricsPeriod1d:  Duration1d,
+		MetricsPeriod1mo: Duration30d,
 	}
 
 	for filter, entries := range p.Entries {

internal/metrics/period/poller.go

@@ -41,6 +41,9 @@ const (
 	gatherErrsInterval = 30 * time.Second
 	saveInterval       = 5 * time.Minute
 
+	gatherErrsTicks = int(gatherErrsInterval / PollInterval) // 30
+	saveTicks       = int(saveInterval / PollInterval)       // 300
+
 	saveBaseDir = "data/metrics"
 )
 
@@ -152,15 +155,12 @@ func (p *Poller[T, AggregateT]) Start() {
 	}
 
 	go func() {
-		pollTicker := time.NewTicker(PollInterval)
-		gatherErrsTicker := time.NewTicker(gatherErrsInterval)
-		saveTicker := time.NewTicker(saveInterval)
+		ticker := time.NewTicker(PollInterval)
+		defer ticker.Stop()
+
+		var tickCount int
 
 		defer func() {
-			pollTicker.Stop()
-			gatherErrsTicker.Stop()
-			saveTicker.Stop()
-
 			err := p.save()
 			if err != nil {
 				l.Err(err).Msg("failed to save metrics data")
@@ -176,19 +176,25 @@ func (p *Poller[T, AggregateT]) Start() {
 			select {
 			case <-t.Context().Done():
 				return
-			case <-pollTicker.C:
+			case <-ticker.C:
 				p.pollWithTimeout(t.Context())
-			case <-saveTicker.C:
-				err := p.save()
-				if err != nil {
-					p.appendErr(err)
+
+				tickCount++
+
+				if tickCount%gatherErrsTicks == 0 {
+					errs, ok := p.gatherErrs()
+					if ok {
+						log.Error().Msg(errs)
+					}
+					p.clearErrs()
 				}
-			case <-gatherErrsTicker.C:
-				errs, ok := p.gatherErrs()
-				if ok {
-					log.Error().Msg(errs)
+
+				if tickCount%saveTicks == 0 {
+					err := p.save()
+					if err != nil {
+						p.appendErr(err)
+					}
 				}
-				p.clearErrs()
 			}
 		}
 	}()